Adjustable gastric banding apparatus have provided an effective and substantially less invasive alternative to gastric bypass surgery and other conventional surgical weight loss procedures. Despite the positive outcomes of invasive weight loss procedures, such as gastric bypass surgery, it has been recognized that sustained weight loss can be achieved through a laparoscopically-placed gastric band, for example, the LAP-BAND® (Allergan, Inc., Irvine, Calif.) gastric band or the LAP-BAND AP® (Allergan, Inc., Irvine, Calif.) gastric band. Generally, gastric bands are placed about the cardia, or upper portion, of a patient's stomach forming a stoma that restricts the food's passage into a lower portion of the stomach. When the stoma is of an appropriate size that is restricted by a gastric band, the food is held in the upper portion of the stomach provides a feeling of satiety or fullness that discourages overeating. Unlike gastric bypass procedures, gastric band apparatus are reversible and require no permanent modification to the gastrointestinal tract.
Over time, a stoma created by a gastric band may need adjustment in order to maintain an appropriate size, which is neither too restrictive nor too passive. Accordingly, prior art gastric band systems provide a subcutaneous fluid access port connected to an expandable or inflatable portion of the gastric band. By adding fluid to or removing fluid from the inflatable portion by means of a hypodermic needle inserted into the access port, the effective size of the gastric band can be adjusted to provide a tighter or looser constriction. Naturally, it would be desirable to allow for non-invasive adjustment of gastric band constriction, for example, without the use of a hypodermic needle.
Birk, et al., U.S. Patent Pub. No. 2010-0010291, and Birk, et al., U.S. Ser. No. 12/705,245, which are commonly-assigned and co-pending with the present application, are incorporated herein in their entirety by this specific reference. Both of these applications disclose certain approaches to implantable pumping systems that may be relevant.
Jordan, et al., U.S. Patent Application Pub. Nos. 2008/0108862 and 2005/0104457, and Jordan, et al., U.S. Pat. No. 7,314,443 generally disclose an implantable device that utilizes a stepper motor to move a fluid utilized by the implantable device. However, these documents do not disclose a system for changing a diameter of a reservoir to inflate an inflatable portion of a gastric band.
Bachmann, U.S. Patent Application Pub. Nos. 2008/0002746 and 2005/0251182, Bachmann, et al., U.S. Patent Application Pub. Nos. 2005/0143766 and 2005/0143765, and Bachmann, U.S. Pat. No. 7,238,191 generally disclose a surgical ring that has an adjustable diameter. The diameter is adjusted using a screw thread that lengthens and shortens using a motor. However, these documents do not disclose a system for moving fluid from a reservoir to an inflatable portion of a gastric band.
Forsell, U.S. Patent Application Pub. No. 2001/0011543 and Forsell, U.S. Pat. No. 6,210,347, generally disclose an adjustable implantable device for restricting an opening in the body that food passes through. The implantable device is mechanically adjustable, but these documents do not disclose a system for adjusting the implantable device using fluid from a flexible reservoir.
Some mechanically adjustable implantable devices have a disadvantage of becoming inoperable if the adjustment mechanism fails. Furthermore, because the motor and the driving mechanisms are located near the restricting band itself, they are more subject to strain and damage from the implantation process. Therefore, it is desirable to develop a remotely adjustable gastric band where the motor is separated from the restricting band to reduce the strain from the implantation process such that the risk of damage during implantation is decreased.
Some attempts have been made to use piezoelectric pumps to drive fluid into an inflatable portion of a gastric band, but these pumps may not provide sufficient pumping power and/or may not satisfy other design specifications. Thus, it is desirable to develop a more efficient pumping mechanism.
Additionally, some attempts have been made to utilize a piezoelectrically driven bellows infuser to inflate an inflatable portion of a gastric band. However, these bellows infusers do not offer a reduced area against which pressure is applied after an amount of fluid has been pumped into the gastric band, which may result in higher power requirements and more energy dissipation. Therefore, it is desirable to develop a pumping mechanism that offers efficiencies as fluid is moved from a reservoir to a gastric band.
Further, some attempts have been made to measure pressure in various components of implantable systems. But these pressure measurements have generally been limited to measuring pressure in an injection port or in an organ such as the stomach. Therefore, it is desirable to develop a flexible reservoir with a means for measuring the pressure in the reservoir itself.
Thus, there continues to remain a need for more effective implantable pump systems for use with adjustable gastric bands, particularly such implantable pump systems with increased and more efficient pumping capability.